Bearing retainer-indexing means for antifriction die sets



June 6, 1961 w. J. BLAZEK 2,987,348

BEARING RETAINER-INDEXING MEANS FOR ANTIFRICTION DIE SETS Filed Feb. 26,1959 WILLIAM J. BLAZEK BY-CORBETT. MAHONEY,

MILLER & RAMBO,ATT Y5.

United States Patent Ohio Filed Feb. 26, 1959, Ser. No. 795,803

' 2 Claims. (Cl. 308-6) This invention relates to bearing-retainerindexing means for antifriction die sets. More particularly, it relatesto indexing means for the relatively axially movable bearing retainer,guide post, and guide bushing of the die sets of punch presses and otherreciprocating machine tools.

The present invention is an improvement over the structure disclosed inthe patent to Blazek et al. No. 2,846,278 which issued August 5, 1958,and especially over the structure disclosed in FIGURE 7 of such patent.

The present invention aims primarily to provide position-maintainingmeans for the movable bearing retainers of antifriction die set guidingand aligning devices. Such devices are formed customarily so thatapunch-carrying movable holder of a die set is provided with guide postswhich are axially receivable for relative longitudinal movement inlongitudinal holes or bores of stationary bushings carried by acomplemental die holder of the set. In association with these parts,tubular ball-bearing retainers of the movable floating type are arrangedand held so that ball elements carried thereby are disposed in annularreceiving spaces provided between the outer wall surfaces of the postsand the adjacent inner wall surfaces of the bushing bores, the ballelements being disposed in simultaneous contact with post and bushingsurfaces.

This construction is such as to provide for accurately guided andconfined reciprocatory movement on the part of the die andpunch-supporting holders of a die set. The construction eliminatesundesired lateral motion between parts and enables the punch and diemembers of the set to be brought into and out of true forming contactwith work pieces positioned between the same in the press. Suchalignment of the relatively movable die and punch members is madepossible through the use of said ball element guide devices, and resultsin prolonging the working life of the punch and die members, as well asenabling the same to produce more rapidly and accurately formingoperations on work pieces. Such pressure-loaded ballbearing guidingdevices for die sets are disclosed, for example, in the prior patent toConner No. 2,422,774 granted June 24, 1947.

In this type of die set guide apparatus, upon the movement of the postsinto the adjacent ends of the bushing bores, the outer cylindricalsurfaces of the posts engage the ball elements of the retainers andforce the same against the complemental inner cylindrical walls of theassociated bushing bores. Since the diameter of each ball element of thebearing retainers is such that it exceeds slightly the width of theannular spaces which the retainers occupy, each ball element sopositioned is placed under compression by its confined engagement withadjoining post and bushing surfaces. Such loaded or pressure engagementof the ball elements causes the retainers to move linearly with theassociated movable posts but at a relatively reduced or lower rate oftravel. It is important, therefore, in the proper functioning of eachguide that the floating bearing-retainers move at a controlled rateconcomitantly with the posts in providing antifriction guidance, wherebyto minimize wear and maintain positive alignment between the relativelymovable die set parts. r

Because of the floating characteristics of the ballbearing retainers,that is, the absence of any direct physiice cal connection between theretainers and associated posts and bushings, it has been somewhatdiflicult for machinists to so assemble each guide and dispose theretainers so that the bearing elements thereof will maintain theirpre-loaded positions throughout full back and forth stroke movements ofthe guide assembly. If, for example, a retainer should fail to move withits reciprocatory posts, excessive friction, part wear and loosenesswould develop rapidly and impairment and loss of guiding function of theguide assembly would take place.

According to said Patent No. 2,846,278, there was provided-positioningmeans for use in association with such antifriction guide appliances fordie sets, whereby in assembling the parts thereof it was necessary toarrange the parts of the guide assembly in their proper or requiredrelative order in the resulting assembly. Furthermore, this positioningmeans maintained the retainers properly interposed between the posts andbushings in all their working positions and served during activecooperation thereof to preclude movement on the part of said re--tainers to positions in which all the antifriction bearing elementspositioned therein would be removed from simultaneous pressureengagement of associated posts and bushings. 1

The present invention relates particularly to a structure in which theguide bushings are disposed on the upper die holder and the guide postsare located on the lower die holder with the posts and bushings movablerelative verti-- cally during the working stroke of the die members, asdisclosed in FIGURE 7 of said Patent No. 2,846,278. However, theindexing and retaining means of this present invention is an improvementover the means for fioatingly suspending the retainer in an initialpredetermined posi-.-

tion from the associated bushing of each antifriction guide assembly. 1

- Additional objects, advantages, structural and operational featureswill be apparent from the following tie-=- along line 2-2 of FIGURE 1through one of the guide assemblies. I

FIGURE 3 is a horizontal or transverse sectional view taken alongline 33of FIGURE 2.

With reference to the drawing, relatively movable dieholders 10 and 11of a die set are shown and are provided with one or more antifrictionguide assemblies 12, two being shown as an example. Theassemblies 12 areemployed for maintaining the holders 10 and 11, and parts carriedthereby, in proper alignment or position of relative registry duringworking movements of a punch press, or other machine tool, on which sucha die set is mounted.

Each assembly 12, according to this invention, comprises a cylindricalbushing 13 rigidly carried by and depending from an opening formed inthe die holder 10 of the die set. The bushing provides an internalcylindrical mensional limits by machining and otherwise finishing andhardening the same to a true cylindrical contour. 'Ih e member 19 isillustrated as a downwardly movable memher and the member 11 isillustrated as a stationary member but this relationship may be reversedor, in fact, both Patented June 6,1961,

members may be movable since it is the relative movement that isimportant.

Mounted for axial movement in each guide assembly is a tubular,sleeve-like, bearing retainer 16. Each retainer I6 -is' formed withaplurality of" transve'r'se'- relatively spaced openings- 17 constitutingsockets-for therotatable' retention of -a plurality of ball-bearingelements 18, these openings being shown arrangedinvertically-spacedhorizontal rows but otherarrangements are possible}The wall thickness of each retainer 16is1es's than theradial' width ofan annular space 19 formed between each inter fitting set of guidebushings 13 andjpo'sts 15 (FIGURES) when they are disposed in'relatively telescoped relationship. Each bearing element 18; however,possesses adiameter slightly greater than the'radial width of the space19 receivingthe same; This enlarged diameter isimportant'in'theoperation of a guide assembly of this'nature,

in that when abushing-13'and "a post 15 move axially into telescopingrelationship and an associated retainer 16 simultaneously moves axiallytherebetween, the ball-bear ing= elements will'becrowded betweenthe'post'15 and the bushing 13 to place the engaged ball elements 18under compressive forces. The ball elements 18 so engagedare" rotated,with the resultthat the retainer 16 moves axially concomitantly with therelatively moving post 15 and'th'e bushing 13 but at a lower rate oflinear travel. Such relativeaxial motion of the'post 15, the bushing 13,and the retainer 16, is continued as the ball elements 18 areprogressively engaged between the post and bushing producing a positiveguiding. action wherein lateral motion is eliminated and accuracythereby obtained in punch-and die registry;

According to the present invention, there is provided the indexing andpositioning means illustrated best in FIG- URES 2"and' 3.

the=lowerend of the bushing audits other-half depending fromthe'bushing, at the time the post 15 and the bushing 13 are out ofoperative relationship prior to the beginning of the working stroke ofthe press; as shown in'FIGURE 2. However, other indexedrelativepositions are possible. Thi'smeans comprises rneans-for splining theretainer to thebushing-and includes a grooved keyway or'slot 25 which isformed in the inner-surface of thebore -14of thebushingISand extends thefull length thereof being open at-eachend at the corresponding extremityof the-bushing. For cooperating with this keyway slot 25, a keyis provided and may be in the foi'm-of a'suitable stopdevice-but is shown as astud 26 which is-fixed inan opening 27 ad jacent the upper end' of'the'retainer'16 and-extends radially outwardlyinto theslot -25with-clearance-between"its;

c. a a 55 Figure 3, clearance isprovided at the sides of the stud andtheadjacent sides of the slot by having the studof outer end the bottom"of ftheslot. Also,-'as indieatedin less diameter than the slot; To limitdownward movementor dropping of the retainer 16 out of the bushing 13,

an abutmentof suitable form is provided and is shown as'a stop pin orstud 28 in thekeyway slot 25 at a suitable location. This'stud 28isfixed in an opening 29 in the bushing 13 which communicates withthe'slot 25 and the stud'28 extends radially inwardly into the groovebut terminates short-of the-inner surface of the bore 14. As

the retainer 16 is moved downwardly in the bushing 13 by gravity, thestud 26 will'engage the stud 28 and 'fl'oating'ly'" suspend the-retainerfrom'the lower end of the bushing'13;

However, the 'retainer'will be so'suspended that it can'pbe movedupwardly within'the bushing 13.

V In the initial assembling'oftheretainer 16 withinthe bushing 13, inthe example shown, the studf28fwill be located to suspend there'tainer16'with about half its lengthfdepending from the bushing 13amits other half l telescoping'upwardly'thereinj However, one orm'ore Idrop the retainer 16 into the bushing 13 and to thereby 4 t additionalopenings 29a may be provided in bushing 13 to position the stud 28 at adifierent location along the bushing and one or more additional openings27a may be provided in the retainer 16 to position the stud 26 at adifferent location, to index the bushing 13 and post 15 as desired. Theretainer 16'can-be' dropped within the bush ing 13' until the"stud"26carried'thereby engages-thestop pin 28 carried "by thebushin g'13 This relationship will be maintained until" the" die or punch"holder'10 moves downwardlysuificiently to cause the post 15 of eachassembly 12 totelescope the'lower end of the bushing of that assembly.Continued'downward movement of the bushing 13 in the working stroke ofthe press, in the example' sh'own; w'illcaus'e' thebushing 13 and thepost 15 to tel'escope beyondthe relative position shown in FIG- URE '2and the balls '18 of the retainer which are therebetween will bepositively rotated and placed under compres sion 'by the relativelyaxiailyrmoving bushing and post.

The positive rotation thus imparted to the compres sively loaded ballelements 18 causes the retainer 16 to descend 'v'v'itlfthe bushing- 13and move downwardly along the post' 15but 'ata lower rate of travel,which will, in

fact, be substantially one half the rate of-the'downward movement ofthebushing 13 over the post 15 During upward movement' 'ofthe bushing 13; areverse action will take place 'untiI'the position shown" in' FIGURE2"is' reached atwhichtime; the retainer'16 willagain be floatin'g'lysuspendedf from *the bushing" 13 'by means of"en-' agenient of thepin 28with the pin 27.

' Through the u'se' 'of'the indexing and positioning means describei thevertically movable ball bearing-carrying retainerorsleeve"'member 16ofan antiirictiondie set guide assembly is supported or retained againstdownward movement in 'a' redetermined position relative to the associated movabl'e b'iishing 13 and "stationary 'post' 15' of thegu'ideassembly. "Furthermore, the construction of the positioning mean's'ot-the-"present invention is such that the retaine supportingfunction'of the -bu'shing"13 is re leased' or e ved '-aut'omatic'ally'with the descent of the bushingbn r V w be caus'ed POSIfiV'QlY to movelinearly with the associated movable bushing at a controlled relativerate of travel throughout the full working stroke of the movable dieholder-10 'Whenthe-Iafter'returns to its normal 'or starting-positlon'and re'turns the-bushing lli to such position, the retainer member-Mreturns with it and occupies a predetermined position'relative thereto.-At this time, the ball el'einritsj'lS 'of'the'ret'ainer'me'mber 16 arerelieved of the compres ive'rorce's' resulting from theirsimultaneouscontact with contiguous surfaces of the movable andstationary guid members --13 Y and 15 "during a working stroke" and theinterposition of the retainer member;16- with its'ball elemefit's 18}enables the "retainer member 16' to be'movably positioned-in itsestablishdrelation'with'said 'guide mem bars." The re'ta'iner '16,itwill be observed, moves in unison withtheassociated bushing 13'when'the bearing elernnts '18 are' unloadeidg but when said'elernents areloaded or pressure 'confiried b e'twe'en the post" 15 and the bushing13; "the bushirig carriedretfiner holding or indexing means isrereasedtd admit ofindependentr'elative movement of thefret'ain'r 16 withrspect'td'theb1ishing- 13. i

. The indeiii'lg means" extreme1y"=sim 1e and inexpensiv'e niea n veryene'ctiv in themamteriinqica ed:above." sincenie eyway orator zsextends'thefull-lengtli of the bushing F13, it ma y be refined therein bysimple and inexpensivejoperation'si' Furthermore, the stopmembers ordevices26 and 2'8 providef ;simplebut positive stop means for"suspe'r'rding' the retainer 16finlfa predetermined positi'on relativeto the bushing 13. Iris simple to locate thestop'meninerszeandzsjinpredetenninedfixed ldbfations on the respectivemembe'r'sls 'and'l6 and to'thenfiirely' working stroke; "so that theretainer 16"will' embers 13 'and 15; res ectively; of the as-" sembly'12? The telescopie relation between the "guide ment of the stop 26 withthe stop 28. Furthermore, as pointed out above, the positions of thesestops may be varied as desired to selectively position the bushing 13and the retainer 16.

According to the provisions of the patent statutes, the principles ofthis invention have been explained and have been illustrated anddescribed in what is now considered to represent the best embodiment.However, it is to be understood that, within the scope of the appendedclaims, the invention may be practiced otherwise than as specificallyillustrated and described.

Having thus described this invention, what is claimed is:

i. In a die set; upper and lower die-supporting members relativelymovable toward and from one another; a tubular bushing carried by theupper of said members and having an inner surface formed with alongitudinally disposed groove; a guide pin carried by the lower of saidmembers in telescoping, axial alignment with said bushing; aball-bearing retainer positioned between said pin and bushing; a stopdevice carried by and projecting outwardly from said retainer and intothe groove of said bushing, said stop device being slidablelongitudinally within the groove of said bushing; and abutment meanscarried by said bushing and engageable with said stop device forindexing said retainer in a preselected position with respect to saidbushing, said stop device being adjustable to difterent, axially spacedpositions on said retainer so as to vary the indexed position of saidretainer with respect to said bushing.

2. In a die set; upper and lower die-supporting members relativelymovable toward and from one another; a tubular bushing carried by anddepending from the upper of said members and having an inner wallsurface formed with a longitudinally extending key way; a guide pincarried by and projecting upwardly from the lower of said members intelescoping, axial alignment with said bushing; a ball-bearing retainermovably carried between said pin and bushing; and a pair of relativelyengageable stop devices carried respectively by said bushing and saidretainer and extending into the key way of said bushing and operableupon relative engagement to maintain said retainer in a preselectedposition relative to said bushing and to preclude withdrawal of saidretainer from the lower end of said bushing, said stop devices beingrelatively adjustable longitudinally of said key way to vary thepreselected position between said bushing and said retainer.

References Cited in the file of this patent UNITED STATES PATENTS2,422,775 Conner June 24, 1947 2,774,430 Blazek Dec. 18, 1956 2,846,278Blazek Aug. 5, 1958

